mcs/class/corlib/System.IO/File.cs

   1 //
   2 // System.IO.File.cs
   3 //
   4 //
   5 // Authors:
   6 //   Miguel de Icaza (miguel@ximian.com)
   7 //   Jim Richardson  (develop@wtfo-guru.com)
   8 //   Dan Lewis       (dihlewis@yahoo.co.uk)
   9 //   Ville Palo      (vi64pa@kolumbus.fi)
  10 //
  11 // Copyright 2002 Ximian, Inc. http://www.ximian.com
  12 // Copyright (C) 2001 Moonlight Enterprises, All Rights Reserved
  13 // Copyright (C) 2004, 2006, 2010 Novell, Inc (http://www.novell.com)
  14 //
  15 // Permission is hereby granted, free of charge, to any person obtaining
  16 // a copy of this software and associated documentation files (the
  17 // "Software"), to deal in the Software without restriction, including
  18 // without limitation the rights to use, copy, modify, merge, publish,
  19 // distribute, sublicense, and/or sell copies of the Software, and to
  20 // permit persons to whom the Software is furnished to do so, subject to
  21 // the following conditions:
  22 //
  23 // The above copyright notice and this permission notice shall be
  24 // included in all copies or substantial portions of the Software.
  25 //
  26 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  30 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  31 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  32 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  33 //
  34
  35 using System;
  36 using System.Collections.Generic;
  37 using System.Diagnostics;
  38 using System.Security;
  39 using System.Text;
  40 using System.Runtime.InteropServices;
  41
  42 #if !NET_2_1
  43 using System.Security.AccessControl;
  44 #endif
  45
  46 namespace System.IO
  47 {
  48         [ComVisible (true)]
  49         public static class File
  50         {
  51                 public static void AppendAllText (string path, string contents)
  52                 {
  53                         using (TextWriter w = new StreamWriter (path, true)) {
  54                                 w.Write (contents);
  55                         }
  56                 }
  57
  58                 public static void AppendAllText (string path, string contents, Encoding encoding)
  59                 {
  60                         using (TextWriter w = new StreamWriter (path, true, encoding)) {
  61                                 w.Write (contents);
  62                         }
  63                 }
  64
  65                 public static StreamWriter AppendText (string path)
  66                 {
  67                         return new StreamWriter (path, true);
  68                 }
  69
  70                 public static void Copy (string sourceFileName, string destFileName)
  71                 {
  72                         Copy (sourceFileName, destFileName, false);
  73                 }
  74
  75                 public static void Copy (string sourceFileName, string destFileName, bool overwrite)
  76                 {
  77                         MonoIOError error;
  78
  79                         if (sourceFileName == null)
  80                                 throw new ArgumentNullException ("sourceFileName");
  81                         if (destFileName == null)
  82                                 throw new ArgumentNullException ("destFileName");
  83                         if (sourceFileName.Length == 0)
  84                                 throw new ArgumentException ("An empty file name is not valid.", "sourceFileName");
  85                         if (sourceFileName.Trim ().Length == 0 || sourceFileName.IndexOfAny (Path.InvalidPathChars) != -1)
  86                                 throw new ArgumentException ("The file name is not valid.");
  87                         if (destFileName.Length == 0)
  88                                 throw new ArgumentException ("An empty file name is not valid.", "destFileName");
  89                         if (destFileName.Trim ().Length == 0 || destFileName.IndexOfAny (Path.InvalidPathChars) != -1)
  90                                 throw new ArgumentException ("The file name is not valid.");
  91
  92                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
  93
  94                         if (!MonoIO.Exists (sourceFileName, out error))
  95                                 throw new FileNotFoundException (Locale.GetText ("{0} does not exist", sourceFileName), sourceFileName);
  96                         if ((GetAttributes (sourceFileName) & FileAttributes.Directory) == FileAttributes.Directory)
  97                                 throw new ArgumentException (Locale.GetText ("{0} is a directory", sourceFileName));
  98
  99                         if (MonoIO.Exists (destFileName, out error)) {
 100                                 if ((GetAttributes (destFileName) & FileAttributes.Directory) == FileAttributes.Directory)
 101                                         throw new ArgumentException (Locale.GetText ("{0} is a directory", destFileName));
 102                                 if (!overwrite)
 103                                         throw new IOException (Locale.GetText ("{0} already exists", destFileName));
 104                         }
 105
 106                         string DirName = Path.GetDirectoryName (destFileName);
 107                         if (DirName != String.Empty && !Directory.Exists (DirName))
 108                                 throw new DirectoryNotFoundException (Locale.GetText ("Destination directory not found: {0}",DirName));
 109
 110                         if (!MonoIO.CopyFile (sourceFileName, destFileName, overwrite, out error)) {
 111                                 string p = Locale.GetText ("{0}\" or \"{1}", sourceFileName, destFileName);
 112                                 throw MonoIO.GetException (p, error);
 113                         }
 114                 }
 115
 116                 public static FileStream Create (string path)
 117                 {
 118                         return Create (path, 8192);
 119                 }
 120
 121                 public static FileStream Create (string path, int bufferSize)
 122                 {
 123                         return new FileStream (path, FileMode.Create, FileAccess.ReadWrite,
 124                                 FileShare.None, bufferSize);
 125                 }
 126
 127 #if !NET_2_1
 128                 [MonoLimitation ("FileOptions are ignored")]
 129                 public static FileStream Create (string path, int bufferSize,
 130                                                  FileOptions options)
 131                 {
 132                         return Create (path, bufferSize, options, null);
 133                 }
 134
 135                 [MonoLimitation ("FileOptions and FileSecurity are ignored")]
 136                 public static FileStream Create (string path, int bufferSize,
 137                                                  FileOptions options,
 138                                                  FileSecurity fileSecurity)
 139                 {
 140                         return new FileStream (path, FileMode.Create, FileAccess.ReadWrite,
 141                                 FileShare.None, bufferSize, options);
 142                 }
 143 #endif
 144
 145                 public static StreamWriter CreateText (string path)
 146                 {
 147                         return new StreamWriter (path, false);
 148                 }
 149
 150                 public static void Delete (string path)
 151                 {
 152                         Path.Validate (path);
 153                         if (Directory.Exists (path))
 154                                 throw new UnauthorizedAccessException(Locale.GetText ("{0} is a directory", path));
 155
 156                         string DirName = Path.GetDirectoryName(path);
 157                         if (DirName != String.Empty && !Directory.Exists (DirName))
 158                                 throw new DirectoryNotFoundException (Locale.GetText ("Could not find a part of the path \"{0}\".", path));
 159
 160                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 161
 162                         MonoIOError error;
 163
 164                         if (!MonoIO.DeleteFile (path, out error)){
 165                                 if (error != MonoIOError.ERROR_FILE_NOT_FOUND)
 166                                         throw MonoIO.GetException (path, error);
 167                         }
 168                 }
 169
 170                 public static bool Exists (string path)
 171                 {
 172                         // For security reasons no exceptions are
 173                         // thrown, only false is returned if there is
 174                         // any problem with the path or permissions.
 175                         // Minimizes what information can be
 176                         // discovered by using this method.
 177                         if (String.IsNullOrWhiteSpace (path) || path.IndexOfAny(Path.InvalidPathChars) >= 0)
 178                                 return false;
 179
 180                         // on Moonlight this does not throw but returns false
 181                         if (!SecurityManager.CheckElevatedPermissions ())
 182                                 return false;
 183
 184                         MonoIOError error;
 185                         return MonoIO.ExistsFile (path, out error);
 186                 }
 187
 188 #if !NET_2_1
 189                 public static FileSecurity GetAccessControl (string path)
 190                 {
 191                         // AccessControlSections.Audit requires special permissions.
 192                         return GetAccessControl (path,
 193                                                  AccessControlSections.Owner |
 194                                                  AccessControlSections.Group |
 195                                                  AccessControlSections.Access);
 196                 }
 197
 198                 public static FileSecurity GetAccessControl (string path, AccessControlSections includeSections)
 199                 {
 200                         return new FileSecurity (path, includeSections);
 201                 }
 202 #endif
 203
 204                 public static FileAttributes GetAttributes (string path)
 205                 {
 206                         Path.Validate (path);
 207                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 208
 209                         MonoIOError error;
 210                         FileAttributes attrs;
 211
 212                         attrs = MonoIO.GetFileAttributes (path, out error);
 213                         if (error != MonoIOError.ERROR_SUCCESS)
 214                                 throw MonoIO.GetException (path, error);
 215                         return attrs;
 216                 }
 217
 218                 public static DateTime GetCreationTime (string path)
 219                 {
 220                         MonoIOStat stat;
 221                         MonoIOError error;
 222                         Path.Validate (path);
 223                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 224
 225                         if (!MonoIO.GetFileStat (path, out stat, out error)) {
 226                                 if (error == MonoIOError.ERROR_PATH_NOT_FOUND || error == MonoIOError.ERROR_FILE_NOT_FOUND)
 227                                         return DefaultLocalFileTime;
 228                                 else
 229                                         throw new IOException (path);
 230                         }
 231                         return DateTime.FromFileTime (stat.CreationTime);
 232                 }
 233
 234                 public static DateTime GetCreationTimeUtc (string path)
 235                 {
 236                         return GetCreationTime (path).ToUniversalTime ();
 237                 }
 238
 239                 public static DateTime GetLastAccessTime (string path)
 240                 {
 241                         MonoIOStat stat;
 242                         MonoIOError error;
 243                         Path.Validate (path);
 244                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 245
 246                         if (!MonoIO.GetFileStat (path, out stat, out error)) {
 247                                 if (error == MonoIOError.ERROR_PATH_NOT_FOUND || error == MonoIOError.ERROR_FILE_NOT_FOUND)
 248                                         return DefaultLocalFileTime;
 249                                 else
 250                                         throw new IOException (path);
 251                         }
 252                         return DateTime.FromFileTime (stat.LastAccessTime);
 253                 }
 254
 255                 public static DateTime GetLastAccessTimeUtc (string path)
 256                 {
 257                         return GetLastAccessTime (path).ToUniversalTime ();
 258                 }
 259
 260                 public static DateTime GetLastWriteTime (string path)
 261                 {
 262                         MonoIOStat stat;
 263                         MonoIOError error;
 264                         Path.Validate (path);
 265                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 266
 267                         if (!MonoIO.GetFileStat (path, out stat, out error)) {
 268                                 if (error == MonoIOError.ERROR_PATH_NOT_FOUND || error == MonoIOError.ERROR_FILE_NOT_FOUND)
 269                                         return DefaultLocalFileTime;
 270                                 else
 271                                         throw new IOException (path);
 272                         }
 273                         return DateTime.FromFileTime (stat.LastWriteTime);
 274                 }
 275
 276                 public static DateTime GetLastWriteTimeUtc (string path)
 277                 {
 278                         return GetLastWriteTime (path).ToUniversalTime ();
 279                 }
 280
 281                 public static void Move (string sourceFileName, string destFileName)
 282                 {
 283                         if (sourceFileName == null)
 284                                 throw new ArgumentNullException ("sourceFileName");
 285                         if (destFileName == null)
 286                                 throw new ArgumentNullException ("destFileName");
 287                         if (sourceFileName.Length == 0)
 288                                 throw new ArgumentException ("An empty file name is not valid.", "sourceFileName");
 289                         if (sourceFileName.Trim ().Length == 0 || sourceFileName.IndexOfAny (Path.InvalidPathChars) != -1)
 290                                 throw new ArgumentException ("The file name is not valid.");
 291                         if (destFileName.Length == 0)
 292                                 throw new ArgumentException ("An empty file name is not valid.", "destFileName");
 293                         if (destFileName.Trim ().Length == 0 || destFileName.IndexOfAny (Path.InvalidPathChars) != -1)
 294                                 throw new ArgumentException ("The file name is not valid.");
 295
 296                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 297
 298                         MonoIOError error;
 299                         if (!MonoIO.Exists (sourceFileName, out error))
 300                                 throw new FileNotFoundException (Locale.GetText ("{0} does not exist", sourceFileName), sourceFileName);
 301
 302                         // Don't check for this error here to allow the runtime
 303                         // to check if sourceFileName and destFileName are equal.
 304                         // Comparing sourceFileName and destFileName is not enough.
 305                         //if (MonoIO.Exists (destFileName, out error))
 306                         //      throw new IOException (Locale.GetText ("{0} already exists", destFileName));
 307
 308                         string DirName;
 309                         DirName = Path.GetDirectoryName (destFileName);
 310                         if (DirName != String.Empty && !Directory.Exists (DirName))
 311                                 throw new DirectoryNotFoundException (Locale.GetText ("Could not find a part of the path."));
 312
 313                         if (!MonoIO.MoveFile (sourceFileName, destFileName, out error)) {
 314                                 if (error == MonoIOError.ERROR_ALREADY_EXISTS)
 315                                         throw MonoIO.GetException (error);
 316                                 else if (error == MonoIOError.ERROR_SHARING_VIOLATION)
 317                                         throw MonoIO.GetException (sourceFileName, error);
 318
 319                                 throw MonoIO.GetException (error);
 320                         }
 321                 }
 322
 323                 public static FileStream Open (string path, FileMode mode)
 324                 {
 325                         return new FileStream (path, mode, mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite, FileShare.None);
 326                 }
 327
 328                 public static FileStream Open (string path, FileMode mode, FileAccess access)
 329                 {
 330                         return new FileStream (path, mode, access, FileShare.None);
 331                 }
 332
 333                 public static FileStream Open (string path, FileMode mode, FileAccess access,
 334                                                FileShare share)
 335                 {
 336                         return new FileStream (path, mode, access, share);
 337                 }
 338
 339                 public static FileStream OpenRead (string path)
 340                 {
 341                         return new FileStream (path, FileMode.Open, FileAccess.Read, FileShare.Read);
 342                 }
 343
 344                 public static StreamReader OpenText (string path)
 345                 {
 346                         return new StreamReader (path);
 347                 }
 348
 349                 public static FileStream OpenWrite (string path)
 350                 {
 351                         return new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None);
 352                 }
 353
 354                 public static void Replace (string sourceFileName,
 355                                             string destinationFileName,
 356                                             string destinationBackupFileName)
 357                 {
 358                         Replace (sourceFileName, destinationFileName, destinationBackupFileName, false);
 359                 }
 360
 361                 public static void Replace (string sourceFileName,
 362                                             string destinationFileName,
 363                                             string destinationBackupFileName,
 364                                             bool ignoreMetadataErrors)
 365                 {
 366                         MonoIOError error;
 367
 368                         if (sourceFileName == null)
 369                                 throw new ArgumentNullException ("sourceFileName");
 370                         if (destinationFileName == null)
 371                                 throw new ArgumentNullException ("destinationFileName");
 372                         if (sourceFileName.Trim ().Length == 0 || sourceFileName.IndexOfAny (Path.InvalidPathChars) != -1)
 373                                 throw new ArgumentException ("sourceFileName");
 374                         if (destinationFileName.Trim ().Length == 0 || destinationFileName.IndexOfAny (Path.InvalidPathChars) != -1)
 375                                 throw new ArgumentException ("destinationFileName");
 376
 377                         string fullSource = Path.GetFullPath (sourceFileName);
 378                         string fullDest = Path.GetFullPath (destinationFileName);
 379                         if (MonoIO.ExistsDirectory (fullSource, out error))
 380                                 throw new IOException (Locale.GetText ("{0} is a directory", sourceFileName));
 381                         if (MonoIO.ExistsDirectory (fullDest, out error))
 382                                 throw new IOException (Locale.GetText ("{0} is a directory", destinationFileName));
 383
 384                         if (!Exists (fullSource))
 385                                 throw new FileNotFoundException (Locale.GetText ("{0} does not exist", sourceFileName),
 386                                                                  sourceFileName);
 387                         if (!Exists (fullDest))
 388                                 throw new FileNotFoundException (Locale.GetText ("{0} does not exist", destinationFileName),
 389                                                                  destinationFileName);
 390                         if (fullSource == fullDest)
 391                                 throw new IOException (Locale.GetText ("Source and destination arguments are the same file."));
 392
 393                         string fullBackup = null;
 394                         if (destinationBackupFileName != null) {
 395                                 if (destinationBackupFileName.Trim ().Length == 0 ||
 396                                     destinationBackupFileName.IndexOfAny (Path.InvalidPathChars) != -1)
 397                                         throw new ArgumentException ("destinationBackupFileName");
 398
 399                                 fullBackup = Path.GetFullPath (destinationBackupFileName);
 400                                 if (MonoIO.ExistsDirectory (fullBackup, out error))
 401                                         throw new IOException (Locale.GetText ("{0} is a directory", destinationBackupFileName));
 402                                 if (fullSource == fullBackup)
 403                                         throw new IOException (Locale.GetText ("Source and backup arguments are the same file."));
 404                                 if (fullDest == fullBackup)
 405                                         throw new IOException (Locale.GetText (
 406                                                                "Destination and backup arguments are the same file."));
 407                         }
 408
 409                         if (!MonoIO.ReplaceFile (fullSource, fullDest, fullBackup,
 410                                                  ignoreMetadataErrors, out error)) {
 411                                 throw MonoIO.GetException (error);
 412                         }
 413                 }
 414
 415 #if !NET_2_1
 416                 public static void SetAccessControl (string path,
 417                                                      FileSecurity fileSecurity)
 418                 {
 419                         if (null == fileSecurity)
 420                                 throw new ArgumentNullException ("fileSecurity");
 421
 422                         fileSecurity.PersistModifications (path);
 423                 }
 424 #endif
 425
 426                 public static void SetAttributes (string path,
 427                                                   FileAttributes fileAttributes)
 428                 {
 429                         MonoIOError error;
 430                         Path.Validate (path);
 431
 432                         if (!MonoIO.SetFileAttributes (path, fileAttributes, out error))
 433                                 throw MonoIO.GetException (path, error);
 434                 }
 435
 436                 public static void SetCreationTime (string path, DateTime creationTime)
 437                 {
 438                         MonoIOError error;
 439                         Path.Validate (path);
 440                         if (!MonoIO.Exists (path, out error))
 441                                 throw MonoIO.GetException (path, error);
 442                         if (!MonoIO.SetCreationTime (path, creationTime, out error))
 443                                 throw MonoIO.GetException (path, error);
 444                 }
 445
 446                 public static void SetCreationTimeUtc (string path, DateTime creationTimeUtc)
 447                 {
 448                         SetCreationTime (path, creationTimeUtc.ToLocalTime ());
 449                 }
 450
 451                 public static void SetLastAccessTime (string path, DateTime lastAccessTime)
 452                 {
 453                         MonoIOError error;
 454                         Path.Validate (path);
 455                         if (!MonoIO.Exists (path, out error))
 456                                 throw MonoIO.GetException (path, error);
 457                         if (!MonoIO.SetLastAccessTime (path, lastAccessTime, out error))
 458                                 throw MonoIO.GetException (path, error);
 459                 }
 460
 461                 public static void SetLastAccessTimeUtc (string path, DateTime lastAccessTimeUtc)
 462                 {
 463                         SetLastAccessTime (path, lastAccessTimeUtc.ToLocalTime ());
 464                 }
 465
 466                 public static void SetLastWriteTime (string path,
 467                                                      DateTime lastWriteTime)
 468                 {
 469                         MonoIOError error;
 470                         Path.Validate (path);
 471                         if (!MonoIO.Exists (path, out error))
 472                                 throw MonoIO.GetException (path, error);
 473                         if (!MonoIO.SetLastWriteTime (path, lastWriteTime, out error))
 474                                 throw MonoIO.GetException (path, error);
 475                 }
 476
 477                 public static void SetLastWriteTimeUtc (string path,
 478                                                      DateTime lastWriteTimeUtc)
 479                 {
 480                         SetLastWriteTime (path, lastWriteTimeUtc.ToLocalTime ());
 481                 }
 482
 483                 //
 484                 // The documentation for this method is most likely wrong, it
 485                 // talks about doing a "binary read", but the remarks say
 486                 // that this "detects the encoding".
 487                 //
 488                 // This can not detect and do anything useful with the encoding
 489                 // since the result is a byte [] not a char [].
 490                 //
 491                 public static byte [] ReadAllBytes (string path)
 492                 {
 493                         using (FileStream s = OpenRead (path)) {
 494                                 long size = s.Length;
 495                                 // limited to 2GB according to http://msdn.microsoft.com/en-us/library/system.io.file.readallbytes.aspx
 496                                 if (size > Int32.MaxValue)
 497                                         throw new IOException ("Reading more than 2GB with this call is not supported");
 498
 499                                 int pos = 0;
 500                                 int count = (int) size;
 501                                 byte [] result = new byte [size];
 502                                 while (count > 0) {
 503                                         int n = s.Read (result, pos, count);
 504                                         if (n == 0)
 505                                                 throw new IOException ("Unexpected end of stream");
 506                                         pos += n;
 507                                         count -= n;
 508                                 }
 509                                 return result;
 510                         }
 511                 }
 512
 513                 public static string [] ReadAllLines (string path)
 514                 {
 515                         using (StreamReader reader = File.OpenText (path)) {
 516                                 return ReadAllLines (reader);
 517                         }
 518                 }
 519
 520                 public static string [] ReadAllLines (string path, Encoding encoding)
 521                 {
 522                         using (StreamReader reader = new StreamReader (path, encoding)) {
 523                                 return ReadAllLines (reader);
 524                         }
 525                 }
 526
 527                 static string [] ReadAllLines (StreamReader reader)
 528                 {
 529                         List<string> list = new List<string> ();
 530                         while (!reader.EndOfStream)
 531                                 list.Add (reader.ReadLine ());
 532                         return list.ToArray ();
 533                 }
 534
 535                 public static string ReadAllText (string path)
 536                 {
 537                         using (StreamReader sr = new StreamReader (path)) {
 538                                 return sr.ReadToEnd ();
 539                         }
 540                 }
 541
 542                 public static string ReadAllText (string path, Encoding encoding)
 543                 {
 544                         using (StreamReader sr = new StreamReader (path, encoding)) {
 545                                 return sr.ReadToEnd ();
 546                         }
 547                 }
 548
 549                 public static void WriteAllBytes (string path, byte [] bytes)
 550                 {
 551                         using (Stream stream = File.Create (path)) {
 552                                 stream.Write (bytes, 0, bytes.Length);
 553                         }
 554                 }
 555
 556                 public static void WriteAllLines (string path, string [] contents)
 557                 {
 558                         using (StreamWriter writer = new StreamWriter (path)) {
 559                                 WriteAllLines (writer, contents);
 560                         }
 561                 }
 562
 563                 public static void WriteAllLines (string path, string [] contents, Encoding encoding)
 564                 {
 565                         using (StreamWriter writer = new StreamWriter (path, false, encoding)) {
 566                                 WriteAllLines (writer, contents);
 567                         }
 568                 }
 569
 570                 static void WriteAllLines (StreamWriter writer, string [] contents)
 571                 {
 572                         foreach (string line in contents)
 573                                 writer.WriteLine (line);
 574                 }
 575
 576                 public static void WriteAllText (string path, string contents)
 577                 {
 578                         WriteAllText (path, contents, EncodingHelper.UTF8Unmarked);
 579                 }
 580
 581                 public static void WriteAllText (string path, string contents, Encoding encoding)
 582                 {
 583                         using (StreamWriter sw = new StreamWriter (path, false, encoding)) {
 584                                 sw.Write (contents);
 585                         }
 586                 }
 587
 588                 static DateTime? defaultLocalFileTime;
 589                 static DateTime DefaultLocalFileTime {
 590                         get {
 591                                 if (defaultLocalFileTime == null)
 592                                         defaultLocalFileTime = new DateTime (1601, 1, 1).ToLocalTime ();
 593
 594                                 return defaultLocalFileTime.Value;
 595                         }
 596                 }
 597
 598
 599                 [MonoLimitation ("File encryption isn't supported (even on NTFS).")]
 600                 public static void Encrypt (string path)
 601                 {
 602                         // MS.NET support this only on NTFS file systems, i.e. it's a file-system (not a framework) feature.
 603                         // otherwise it throws a NotSupportedException (or a PlatformNotSupportedException on older OS).
 604                         // we throw the same (instead of a NotImplementedException) because most code should already be
 605                         // handling this exception to work properly.
 606                         throw new NotSupportedException (Locale.GetText ("File encryption isn't supported on any file system."));
 607                 }
 608
 609                 [MonoLimitation ("File encryption isn't supported (even on NTFS).")]
 610                 public static void Decrypt (string path)
 611                 {
 612                         // MS.NET support this only on NTFS file systems, i.e. it's a file-system (not a framework) feature.
 613                         // otherwise it throws a NotSupportedException (or a PlatformNotSupportedException on older OS).
 614                         // we throw the same (instead of a NotImplementedException) because most code should already be
 615                         // handling this exception to work properly.
 616                         throw new NotSupportedException (Locale.GetText ("File encryption isn't supported on any file system."));
 617                 }
 618
 619                 public static IEnumerable<string> ReadLines (string path)
 620                 {
 621                         return ReadLines (File.OpenText (path));
 622                 }
 623
 624                 public static IEnumerable<string> ReadLines (string path, Encoding encoding)
 625                 {
 626                         return ReadLines (new StreamReader (path, encoding));
 627                 }
 628
 629                 // refactored in order to avoid compiler-generated names for Moonlight tools
 630                 static IEnumerable<string> ReadLines (StreamReader reader)
 631                 {
 632                         using (reader) {
 633                                 string s;
 634                                 while ((s = reader.ReadLine ()) != null) {
 635                                         yield return s;
 636                                 }
 637                         }
 638                 }
 639
 640                 public static void AppendAllLines (string path, IEnumerable<string> contents)
 641                 {
 642                         Path.Validate (path);
 643
 644                         if (contents == null)
 645                                 return;
 646
 647                         using (TextWriter w = new StreamWriter (path, true)) {
 648                                 foreach (var line in contents)
 649                                         w.WriteLine (line);
 650                         }
 651                 }
 652
 653                 public static void AppendAllLines (string path, IEnumerable<string> contents, Encoding encoding)
 654                 {
 655                         Path.Validate (path);
 656
 657                         if (contents == null)
 658                                 return;
 659
 660                         using (TextWriter w = new StreamWriter (path, true, encoding)) {
 661                                 foreach (var line in contents)
 662                                         w.WriteLine (line);
 663                         }
 664                 }
 665
 666                 public static void WriteAllLines (string path, IEnumerable<string> contents)
 667                 {
 668                         Path.Validate (path);
 669
 670                         if (contents == null)
 671                                 return;
 672
 673                         using (TextWriter w = new StreamWriter (path, false)) {
 674                                 foreach (var line in contents)
 675                                         w.WriteLine (line);
 676                         }
 677                 }
 678
 679                 public static void WriteAllLines (string path, IEnumerable<string> contents, Encoding encoding)
 680                 {
 681                         Path.Validate (path);
 682
 683                         if (contents == null)
 684                                 return;
 685
 686                         using (TextWriter w = new StreamWriter (path, false, encoding)) {
 687                                 foreach (var line in contents)
 688                                         w.WriteLine (line);
 689                         }
 690                 }
 691         }
 692 }